1. Field of the Invention
The present invention relates to an anti-theft system for vehicles, and more particularly to an anti-theft system that operates to immobilize a vehicle both by maintaining the hydraulic brakes of a stationary vehicle in an engaged condition and by disabling various parts of the vehicle electrical systems, to prevent unintended movement of the vehicle by an unauthorized person.
2. Description of the Related Art
Various types of structural arrangements for preventing theft of and unauthorized use of a vehicle are known. Several such arrangements have been suggested over the years, and examples of arrangements that are now in use include steering wheel locks, to prevent turning of the steering wheel when the ignition key is removed, electronically operated door locking systems, and various types of vehicle alarm systems to provide either or both audible alarms and visual alarms, the latter usually in the form of flashing headlights. Steering wheel locks are universally provided as standard equipment on all modern passenger vehicles, while electronically operated door locking systems and alarm systems are provided as standard equipment on only some of such vehicles. None of the devices that are presently available commercially has successfully prevented vehicle theft when they are confronted by a resourceful and determined thief.
The sales of vehicle alarm systems have increased significantly in recent years. However, that type of system places principal reliance upon either the deterrent effect on a thief of an audible alarm or of a visible alarm, which often does not have the desired deterrent effect, or, alternatively, on the intervention by a third party, such as a bystander, to intervene to help prevent the theft of the vehicle. However, third parties, including bystanders, often fear involvement in such activities, and more often than not they decline to intervene. Consequently, even vehicle alarm systems provide no guarantee against vehicle theft.
Because of the shortcomings of existing theft prevention arrangements and systems, some system for automatically and completely immobilizing a vehicle by the vehicle operator presents the most feasible way of preventing vehicle theft or unauthorized use, one that does not rely on audible or visual deterrents or on third party intervention. In that regard, several vehicle immobilization systems that include brake system lockup have been proposed in the past. Examples of such systems are disclosed in U.S. Pat. No. 3,684,049, which issued on Aug. 15, 1972, to Seiji Kimura; U.S. Pat. No. 3,800,279, which issued on Mar. 26, 1974, to Herbert L. Thompson; U.S. Pat. No. 4,018,314, which issued on Apr. 19, 1977, to Raymond Richmond, et al.; U.S. Pat. No. 4,196,939, which issued on Apr. 8, 1980, to George Kavis; U.S. Pat. No. 4,300,057, which issued on Nov. 10, 1981, to Pedro Batlle Crosas; U.S. Pat. No. 4,777,377, which issued on Oct. 11, 1988, to Herman C. Jeter; U.S. Pat. No. 4,951,776, which issued on Aug. 28, 1990, to Herman C. Jeter; U.S. Pat. No. 5,351,781, which issued on Oct. 4, 1994, to Chalmers A. Pritchard, et al.; and U.S. Pat. No. 5,413,197, which issued on May 9, 1995, to Larry G. Baer, et al. None of those systems, however, is in widespread use, and each has limitations that apparently contribute to its lack of broad scale acceptance.
It is an object of the present invention to provide an improved vehicle anti-theft system that operates both to block the vehicle brake system, to prevent vehicle movement, and also to disable elements of the vehicle electrical systems, to prevent unintended and unauthorized movement of the vehicle.